Akka - Extract response body as plain string value in Java

Question

I am facing trouble of extracting the response body as a string value from a http response in Java. I did an attempt with the answers here: akka HttpResponse read body as String scala however I could not find something which would work out. By trail-and-error I came up to the following snippet, however I don't think it should be this difficult. So I am seeking for a simple way to do this. The current code snippet which I am using is:

import akka.actor.ActorSystem;
import akka.http.javadsl.Http;
import akka.http.javadsl.model.HttpRequest;
import akka.http.javadsl.model.HttpResponse;
import akka.stream.javadsl.Sink;
import akka.util.ByteString;
import com.typesafe.config.ConfigFactory;

public class App {

    public static void main(String[] args) {
        ActorSystem actorSystem = ActorSystem.create(ClientConfig.class.getSimpleName(), ConfigFactory.defaultApplication(App.class.getClassLoader()));
        Http httpClient = akka.http.javadsl.Http.get(actorSystem);
        HttpRequest httpRequest = HttpRequest.create("https://stackoverflow.com");

        String responseBody = httpClient.singleRequest(httpRequest)
                .thenApply((HttpResponse httpResponse) ->
                        httpResponse.entity()
                                .getDataBytes()
                                .fold(ByteString.emptyByteString(), ByteString::concat)
                                .map(ByteString::utf8String)
                                .runWith(Sink.head(), actorSystem)
                                .toCompletableFuture()
                                .join())
                .toCompletableFuture()
                .join();

        System.out.println(responseBody);
    }

}

I am just wondering whether the body of the thenApply to transform the entity to a string needs to be this complex or are there other ways within the Akka library itself to simplify it.

In the Scala case you must execute Await on the Future that is created after unmarshall the entity your application to wait until the future is completed — Emiliano Martinez, Jul 26 '23 at 11:16

score 0 · Answer 1 · answered Jul 26 '23 at 13:29

Simple HttpRequest in Scala 3 to get the html string as response:

object HttpTest {

  given system: ActorSystem[_] = ActorSystem(Behaviors.empty, "SingleRequest")
  // needed for the future flatMap/onComplete in the end
  given executionContext: ExecutionContext = system.executionContext
  

  @main def httpExample() = {
    val result = Http().singleRequest(HttpRequest(uri = "https://stackoverflow.com", method = HttpMethods.GET))

    val str = result.map(e => {
        Unmarshal(e.entity).to[String]
      }).flatten

    println(Await.result(str, 10.seconds))
  }
}

Akka - Extract response body as plain string value in Java

1 Answers1